Clinical Outcomes Associated With Various Microvascular Injury Patterns Identified by CMR After STEMI.

BACKGROUND: The prognostic significance of various microvascular injury (MVI) patterns after ST-segment elevation myocardial infarction (STEMI) is not well known. OBJECTIVES: This study sought to investigate the prognostic implications of different MVI patterns in STEMI patients. METHODS: The authors analyzed 1,109 STEMI patients included in 3 prospective studies. Cardiac magnetic resonance (CMR) was performed 3 days (Q1-Q3: 2-5 days) after percutaneous coronary intervention (PCI) and included late gadolinium enhancement imaging for microvascular obstruction (MVO) and T2∗ mapping for intramyocardial hemorrhage (IMH). Patients were categorized into those without MVI (MVO-/IMH-), those with MVO but no IMH (MVO+/IMH-), and those with IMH (IMH+). RESULTS: MVI occurred in 633 (57%) patients, of whom 274 (25%) had an MVO+/IMH- pattern and 359 (32%) had an IMH+ pattern. Infarct size was larger and ejection fraction lower in IMH+ than in MVO+/IMH- and MVO-/IMH- (infarct size: 27% vs 19% vs 18% [P < 0.001]; ejection fraction: 45% vs 50% vs 54% [P < 0.001]). During a median follow-up of 12 months (Q1-Q3: 12-35 months), a clinical outcome event occurred more frequently in IMH+ than in MVO+/IMH- and MVO-/IMH- subgroups (19.5% vs 3.6% vs 4.4%; P < 0.001). IMH+ was the sole independent MVI parameter predicting major adverse cardiovascular events (HR: 3.88; 95% CI: 1.93-7.80; P < 0.001). CONCLUSIONS: MVI is associated with future adverse outcomes only in patients with a hemorrhagic phenotype (IMH+). Patients with only MVO (MVO+/IMH-) had a prognosis similar to patients without MVI (MVO-/IMH-). This highlights the independent prognostic importance of IMH in assessing and managing risk after STEMI.

Mitral annular disjunction in out-of-hospital cardiac arrest patients-a retrospective cardiac MRI study.

BACKGROUND: Mitral annular disjunction (MAD), defined as defective attachment of the mitral annulus to the ventricular myocardium, has recently been linked to malignant arrhythmias. However, its role and prognostic significance in patients requiring cardiopulmonary resuscitation (CPR) remain unknown. This retrospective analysis aimed to describe the prevalence and significance of MAD by cardiac magnetic resonance (CMR) imaging in out-of-hospital cardiac arrest (OHCA) patients. METHODS: Eighty-six patients with OHCA and a CMR scan 5 days after CPR (interquartile range (IQR): 49 days before - 9 days after) were included. MAD was defined as disjunction-extent ≥ 1 mm in CMR long-axis cine-images. Medical records were screened for laboratory parameters, comorbidities, and a history of arrhythmia. RESULTS: In 34 patients (40%), no underlying cause for OHCA was found during hospitalization despite profound diagnostics. Unknown-cause OHCA patients showed a higher prevalence of MAD compared to definite-cause patients (56% vs. 10%, p < 0.001) and had a MAD-extent of 6.3 mm (IQR: 4.4-10.3); moreover, these patients were significantly younger (43 years vs. 61 years, p < 0.001), more often female (74% vs. 21%, p < 0.001) and had fewer comorbidities (hypertension, hypercholesterolemia, coronary artery disease, all p < 0.005). By logistic regression analysis, the presence of MAD remained significantly associated with OHCA of unknown cause (odds ratio: 8.49, 95% confidence interval: 2.37-30.41, p = 0.001) after adjustment for age, presence of hypertension, and hypercholesterolemia. CONCLUSIONS: MAD is rather common in OHCA patients without definitive aetiology undergoing CMR. The presence of MAD was independently associated to OHCA without an identifiable trigger. Further research is needed to understand the exact role of MAD in OHCA patients.

Relation of plasma neuropeptide-Y with myocardial function and infarct severity in acute ST-elevation myocardial infarction.

BACKGROUND: Acute myocardial infarction is associated with the release of the co-transmitter neuropeptide-Y (NPY). NPY acts as a potent vasoconstrictor and is associated with microvascular dysfunction after ST-elevation myocardial infarction (STEMI). This study comprehensively evaluated the association of plasma NPY with myocardial function and infarct severity, visualized by cardiac magnetic resonance (CMR) imaging, in STEMI patients revascularized by primary percutaneous coronary intervention (PCI). METHODS: In this observational study, we included 260 STEMI patients enrolled in the prospective MARINA-STEMI (NCT04113356) study. Plasma NPY concentrations were measured by an immunoassay 24h after PCI from peripheral venous blood samples. Left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), infarct size (IS) and microvascular obstruction (MVO) were determined using CMR imaging. RESULTS: Median plasma concentrations of NPY were 70 [interquartile range (IQR):35-115] pg/ml. NPY levels above median were significantly associated with lower LVEF (48%vs.52%, p=0.004), decreased GLS (-8.8%vs.-12.6%, p<0.001) and larger IS (17%vs.13%, p=0.041) in the acute phase after infarction as well as after 4 months (LVEF:50%vs.52%, p=0.030, GLS:-10.5vs.-12.9,p<0.001,IS:13%vs.10%,p=0.011). In addition, NPY levels were significantly related to presence of MVO (58%vs.52%, p=0.041). Moreover, in multivariable linear regression analysis, NPY remained significantly associated with all investigated CMR parameters (LVEF:p<0.001,GLS:p<0.001,IS:p=0.003,MVO:p=0.042) independent of other established clinical variables including high-sensitivity cardiac troponin T, pre-interventional TIMI flow 0 and left anterior descending artery as culprit lesion location. CONCLUSION: High plasma levels of NPY, measured 24h after STEMI, were independently associated with lower LVEF, decreased GLS, larger IS as well as presence of MVO, indicating plasma NPY as a novel clinical risk marker post STEMI.

Functional aortic valve area differs significantly between sexes: A phase-contrast cardiac MRI study in patients with severe aortic stenosis.

Background: Aortic stenosis (AS) is one of the most prevalent valvular heart-diseases in Europe. Currently, diagnosis and classification are not sex-sensitive; however, due to a distinctly different natural history of AS, further investigations of sex-differences in AS-patients are needed. Thus, this study aimed to detect sex-differences in severe AS, especially concerning flow-patterns, via phase-contrast cardiac magnetic resonance imaging (PC-CMR). Methods: Forty-four severe AS-patients (20 women, 45 % vs. 24 men, 55 %) with a median age of 72 years underwent transthoracic echocardiography (TTE), cardiac catheterization (CC) and CMR. Aortic valve area (AVA) and stroke volume (SV) were determined in all modalities, with CMR yielding geometrical AVA via cine-planimetry and functional AVA via PC-CMR, the latter being also used to examine flow-properties. Results: Geometrical AVA showed no sex-differences (0.91 cm2, IQR: 0.61-1.14 vs. 0.94 cm2, IQR: 0.77-1.22, p = 0.322). However, functional AVA differed significantly between sexes in all three modalities (TTE: p = 0.044; CC/PC-CMR: p < 0.001). In men, no significant intermethodical biases in functional AVA-measurements between modalities were found (p = 0.278); yet, in women the particular measurements differed significantly (p < 0.001). Momentary flowrate showed sex-differences depending on momentary opening-degree (at 50 %, 75 % and 90 % of peak-AVA, all p < 0.001), with men showing higher flowrates with increasing opening-area. In women, flowrate did not differ between 75 % and 90 % of peak-AVA (p = 0.191). Conclusions: In severe AS-patients, functional AVA showed marked sex-differences in all modalities, whilst geometrical AVA did not differ. Inter-methodical biases were negligible in men, but not in women. Lastly, significant sex-differences in flow-patterns fit in with the different pathogenesis of AS.

Culprit Lesion Vessel Size and Risk of Reperfusion Injury in ST-Segment Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study.

BACKGROUND: Microvascular obstruction (MVO) and intramyocardial hemorrhage (IMH) are well-established imaging biomarkers of failed myocardial tissue reperfusion in patients with ST-segment elevation-myocardial infarction treated with percutaneous coronary intervention. MVO and IMH are associated with an increased risk of adverse outcome independent of infarct size, but whether the size of the culprit lesion vessel plays a role in the occurrence and severity of reperfusion injury is currently unknown. This study aimed to evaluate the association between culprit lesion vessel size and the occurrence and severity of reperfusion injury as determined by cardiac magnetic resonance imaging. METHODS AND RESULTS: Patients (n=516) with first-time ST-segment-elevation myocardial infarction underwent evaluation with cardiac magnetic resonance at 4 (3-5) days after infarction. MVO was assessed with late gadolinium enhancement imaging and IMH with T2* mapping. Vessel dimensions were determined using catheter-based reference. Median culprit lesion vessel size was 3.1 (2.7-3.6) mm. MVO and IMH were found in 299 (58%) and 182 (35%) patients. Culprit lesion vessel size was associated with body surface area, diabetes, total ischemic time, postinterventional thrombolysis in myocardial infarction flow, and infarct size. There was no association between vessel size and MVO or IMH in univariable and multivariable analysis (P>0.05). These findings were consistent across patient subgroups with left anterior descending artery and non-left anterior descending artery infarctions and those with thrombolysis in myocardial infarction 3 flow post-percutaneous coronary intervention. CONCLUSIONS: Comprehensive characterization of myocardial tissue reperfusion injury by cardiac magnetic resonance revealed no association between culprit lesion vessel size and the occurrence of MVO and IMH in patients treated with primary percutaneous coronary intervention for ST-segment-elevation myocardial infarction.

Association of dysglycaemia with persistent infarct core iron in patients with acute ST-segment elevation myocardial infarction.

BACKGROUND: Dysglycaemia increases the risk of myocardial infarction and subsequent recurrent cardiovascular events. However, the role of dysglycaemia in ischemia/reperfusion injury with development of irreversible myocardial tissue alterations remains poorly understood. In this study we aimed to investigate the association of ongoing dysglycaemia with persistence of infarct core iron and their longitudinal changes over time in patients undergoing primary percutaneous coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI). METHODS: We analyzed 348 STEMI patients treated with primary PCI between 2016 and 2021 that were included in the prospective MARINA-STEMI study (NCT04113356). Peripheral venous blood samples for glucose and glycated hemoglobin (HbA1c) measurements were drawn on admission and 4 months after STEMI. Cardiac magnetic resonance (CMR) imaging including T2 * mapping for infarct core iron assessment was performed at both time points. Associations of dysglycaemia with persistent infarct core iron and iron resolution at 4 months were calculated using multivariable regression analysis. RESULTS: Intramyocardial hemorrhage was observed in 147 (42%) patients at baseline. Of these, 89 (61%) had persistent infarct core iron 4 months after infarction with increasing rates across HbA1c levels (<5.7%: 33%, ≥5.7: 79%). Persistent infarct core iron was independently associated with ongoing dysglycaemia defined by HbA1c at 4 months (OR: 7.87 [95% CI: 2.60-23.78]; p < 0.001), after adjustment for patient characteristics and CMR parameters. The independent association was present even after exclusion of patients with diabetes (pre- and newly diagnosed, n = 16). CONCLUSIONS: In STEMI patients treated with primary PCI, ongoing dysglycaemia defined by HbA1c is independently associated with persistent infarct core iron and a lower likelihood of iron resolution. These findings suggest a potential association between ongoing dysglycaemia and persistent infarct core iron, which warrants further investigation for therapeutic implications.

Infarct severity and outcomes in ST-elevation myocardial infarction patients without standard modifiable risk factors - A multicenter cardiac magnetic resonance study.

BACKGROUND: Standard modifiable cardiovascular risk factors (SMuRFs) are well-established players in the pathogenesis of ST-elevation myocardial infarction (STEMI). However, in a significant proportion of STEMI patients, no SMuRFs can be identified, and the outcomes of this subgroup are not well described. OBJECTIVES: To assess the infarct characteristics at myocardial-tissue level and subsequent clinical outcomes in SMuRF-less STEMIs. METHODS: This multicenter, individual patient-data analysis included 2012 STEMI patients enrolled in four cardiac magnetic resonance (CMR) imaging studies conducted in Austria, Germany, Scotland, and the Netherlands. Unstable patients at time of CMR (e.g. cardiogenic shock/after cardiac arrest) were excluded. SMuRF-less was defined as absence of hypertension, smoking, hypercholesterolemia, and diabetes mellitus. All patients underwent CMR 3(interquartile range [IQR]:2-4) days after infarction to assess left ventricular (LV) volumes and ejection fraction, infarct size and microvascular obstruction (MVO). Clinical endpoints were defined as major adverse cardiovascular events (MACE), including all-cause mortality, re-infarction and heart failure. RESULTS: No SMuRF was identified in 185 patients (9%). These SMuRF-less patients were older, more often male, had lower TIMI risk score and pre-interventional TIMI flow, and less frequently multivessel-disease. SMuRF-less patients did not show significant differences in CMR markers compared to patients with SMuRFs (all p > 0.10). During a median follow-up of 12 (IQR:12-27) months, 199 patients (10%) experienced a MACE. No significant difference in MACE rates was observed between SMuRF-less patients and patients with SMuRFs (8vs.10%, p = 0.39). CONCLUSIONS: In this large individual patient-data pooled analysis of low-risk STEMI patients, infarct characteristics and clinical outcomes were not different according to SMuRF status.

Association of High-Sensitivity Cardiac Troponin T With 30-Day and 5-Year Mortality After Cardiac Surgery.

BACKGROUND: The relevance of perioperative myocardial injury (PMI) after cardiac surgery for 30-day mortality and long-term survival remains to be determined. OBJECTIVES: This study assessed the association of PMI after cardiac surgery, reflected by postoperative troponin release, with 30-day mortality and long-term survival after: 1) coronary artery bypass grafting (CABG); 2) isolated aortic valve replacement (AVR) surgery; and 3) all other cardiac surgeries. METHODS: A consecutive cohort of 8,292 patients undergoing cardiac surgery with serial perioperative high-sensitivity cardiac troponin T (hs-cTnT) measurements was retrospectively analyzed. The relationship between postoperative hs-cTnT release and 30-day mortality or 5-year mortality was analyzed after adjustment with EuroSCORE II using a Cox proportional hazards model. hs-cTnT thresholds for 30-day and 5-year mortality were determined for isolated CABG (32.3%), AVR (14%), and other cardiac surgery (53.8%). RESULTS: High postoperative hs-cTnT levels were associated with higher 30-day mortality but not 5-year mortality. In CABG, median peak concentration of postoperative hs-cTnT was 1,044 ng/L, in AVR it was 502 ng/L, and in other cardiac surgery it was 1,110 ng/L. hs-cTnT thresholds defining mortality-associated PMI were as follows: for CABG, 2,385 ng/L (170× the upper reference limit of normal in a seemingly healthy population [URL]); for AVR, 568 ng/L (41× URL); and for other cardiac procedures, 1,873 ng/L (134× URL). hs-cTnT levels above the cutoffs resulted in an HR for 30-day mortality for CABG of 12.56 (P < 0.001), for AVR of 4.44 (P = 0.004), and for other cardiac surgery of 3.97 (P < 0.001). CONCLUSIONS: PMI reflected by perioperative hs-cTnT release is associated with the expected 30-day mortality but not 5-year mortality. Postoperative hs-cTnT cutoffs to identify survival-relevant PMI are higher than suggested in current definitions.

Cardiac Magnetic Resonance Imaging Versus Computed Tomography to Guide Transcatheter Aortic Valve Replacement: A Randomized, Open-Label, Noninferiority Trial.

BACKGROUND: Computed tomography (CT) is recommended for guiding transcatheter aortic valve replacement (TAVR). However, a sizable proportion of TAVR candidates have chronic kidney disease, in whom the use of iodinated contrast media is a limitation. Cardiac magnetic resonance imaging (CMR) is a promising alternative, but randomized data comparing the effectiveness of CMR-guided versus CT-guided TAVR are lacking. METHODS: An investigator-initiated, prospective, randomized, open-label, noninferiority trial was conducted at 2 Austrian heart centers. Patients evaluated for TAVR according to the inclusion criteria (severe symptomatic aortic stenosis) and exclusion criteria (contraindication to CMR, CT, or TAVR, a life expectancy <1 year, or chronic kidney disease level 4 or 5) were randomized (1:1) to undergo CMR or CT guiding. The primary outcome was defined according to the Valve Academic Research Consortium-2 definition of implantation success at discharge, including absence of procedural mortality, correct positioning of a single prosthetic valve, and proper prosthetic valve performance. Noninferiority was assessed using a hybrid modified intention-to-treat/per-protocol approach on the basis of an absolute risk difference margin of 9%. RESULTS: Between September 11, 2017, and December 16, 2022, 380 candidates for TAVR were randomized to CMR-guided (191 patients) or CT-guided (189 patients) TAVR planning. Of these, 138 patients (72.3%) in the CMR-guided group and 129 patients (68.3%) in the CT-guided group eventually underwent TAVR (modified intention-to-treat cohort). Of these 267, 19 patients had protocol deviations, resulting in a per-protocol cohort of 248 patients (121 CMR-guided, 127 CT-guided). In the modified intention-to-treat cohort, implantation success was achieved in 129 patients (93.5%) in the CMR group and in 117 patients (90.7%) in the CT group (between-group difference, 2.8% [90% CI, -2.7% to 8.2%]; P<0.01 for noninferiority). In the per-protocol cohort (n=248), the between-group difference was 2.0% (90% CI, -3.8% to 7.8%; P<0.01 for noninferiority). CONCLUSIONS: CMR-guided TAVR was noninferior to CT-guided TAVR in terms of device implantation success. CMR can therefore be considered as an alternative for TAVR planning. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT03831087.

Temporal Trends in Infarct Severity Outcomes in ST-Segment-Elevation Myocardial Infarction: A Cardiac Magnetic Resonance Imaging Study.

Background Severity of myocardial tissue injury is a main determinant of morbidity and death related to ST-segment-elevation myocardial infarction (STEMI). Temporal trends of infarct characteristics at the myocardial tissue level have not been described. This study sought to assess temporal trends in infarct characteristics through a comprehensive assessment by cardiac magnetic resonance imaging at a standardized time point early after STEMI. Methods and Results We analyzed patients with STEMI treated with percutaneous coronary intervention at the University Hospital of Innsbruck who underwent cardiac magnetic resonance imaging between 2005 and 2021. The study period was divided into terciles. Myocardial damage characteristics were assessed using a multiparametric cardiac magnetic resonance imaging protocol within the first week after STEMI and compared between groups. A total of 843 patients with STEMI (17% women) with a median age of 57 (interquartile range, 51-66) years were analyzed. While age, sex, and the clinical risk profile expressed as thrombolysis in myocardial infarction risk score were comparable across the study period, there were differences in guideline-recommended therapies. At the same time, there was no significant change in infarct size (P=0.25), microvascular obstruction (P=0.50), and intramyocardial hemorrhage (P=0.34). Left ventricular remodeling indices and left ventricular ejection fraction remained virtually unchanged (all P>0.05). Major adverse cardiovascular events at 4 (interquartile range, 4-5) months were similar between groups (P=0.36). Conclusions In this magnetic resonance imaging study investigating patients with STEMI treated with primary percutaneous coronary intervention over the past 15 years, no change in infarct severity at the myocardial level has been observed. Clinical research on novel therapeutic approaches to reduce myocardial tissue injury should be a priority.

Smartwatch-derived heart rate variability: a head-to-head comparison with the gold standard in cardiovascular disease.

Aims: We aimed to investigate the concordance between heart rate variability (HRV) derived from the photoplethysmographic (PPG) signal of a commercially available smartwatch compared with the gold-standard high-resolution electrocardiogram (ECG)-derived HRV in patients with cardiovascular disease. Methods and results: We prospectively enrolled 104 survivors of acute ST-elevation myocardial infarction, 129 patients after an ischaemic stroke, and 30 controls. All subjects underwent simultaneous recording of a smartwatch (Garmin vivoactive 4; Garmin Ltd, Olathe, KS, USA)-derived PPG signal and a high-resolution (1000 Hz) ECG for 30 min under standardized conditions. HRV measures in time and frequency domain, non-linear measures, as well as deceleration capacity (DC) were calculated according to previously published technologies from both signals. Lin's concordance correlation coefficient (ρc) between smartwatch-derived and ECG-based HRV markers was used as a measure of diagnostic accuracy. A very high concordance within the whole study cohort was observed for the mean heart rate (ρc = 0.9998), standard deviation of the averages of normal-to-normal (NN) intervals in all 5min segments (SDANN; ρc = 0.9617), and very low frequency power (VLF power; ρc = 0.9613). In contrast, detrended fluctuation analysis (DF-α1; ρc = 0.5919) and the square mean root of the sum of squares of adjacent NN-interval differences (rMSSD; ρc = 0.6617) showed only moderate concordance. Conclusion: Smartwatch-derived HRV provides a practical alternative with excellent accuracy compared with ECG-based HRV for global markers and those characterizing lower frequency components. However, caution is warranted with HRV markers that predominantly assess short-term variability.

Improved detection of echocardiographically occult left ventricular thrombi following ST-elevation myocardial infarction.

AIM: The aim of this study was to investigate predictors of transthoracic echocardiography (TTE)-occult left ventricular (LV) thrombi (LVT) and to propose a clinical model for improved detection of TTE-occult LVT post-ST-elevation myocardial infarction (STEMI). Patients with acute STEMI are at significant risk for developing LVT. However, this complication often (up to 65%) remains undetected by using TTE, referred to as TTE-occult LVT. METHODS AND RESULTS: In total, 870 STEMI patients underwent TTE and cardiac magnetic resonance (CMR), the reference method for LVT detection, 3 days after infarction. Clinical (body mass index, peak cardiac troponin T) and echocardiographic [ejection fraction, apical wall motion scores (AWMSs)] predictors were analysed. Primary endpoint was the presence of TTE-occult LVT identified by CMR imaging. From the overall cohort, 37 patients (4%) showed an LVT by CMR. Of these thrombi, 25 (68%) were not identified by TTE. Transthoracic echocardiography-occult thrombi did not significantly differ in volume (1.4 vs. 2.74 cm3), diameter (19.0 vs. 23.3 mm), and number of fragments or shape compared with TTE-apparent LVT (all P > 0.05). For predicting these TTE-occult LVT, the 16-segment AWMS (AWMS16Seg) showed highest validity {area under the curve: 0.91 [95% confidence interval (CI): 0.89-0.93]; P < 0.001}, with an association independent of ejection fraction and 17-segment AWMS (AWMS17Seg) [odds ratio: 1.68 (95% CI: 1.43-1.97); P < 0.001] and clinical (body mass index, peak troponin) and angiographic (culprit lesion, post-interventional thrombolysis in myocardial infarction flow) associates of TTE-occult LVT (all P < 0.05). Dichotomization at AWMS16Seg ≥ 8 (n = 260, 30%) allowed for a detection of all TTE-occult LVT (sensitivity: 100%), with a corresponding specificity of 77%. CONCLUSION: After acute STEMI, AWMS16Seg served as a simple and very robust predictor of TTE-occult LVT. An AWMS16Seg-based algorithm to identify patients for additional CMR imaging offers great potential to optimize detection of TTE-occult LVT following STEMI.

Slice positioning in phase-contrast MRI impacts aortic stenosis assessment.

AIMS: To determine the phase-contrast cardiovascular magnetic resonance imaging (PC-CMR) slice-position above aortic leaflet-attachment-plane (LAP) that provides flow-velocity, -volume and aortic valve area (AVA) measurements with best agreement to invasive and echocardiographic measurements in aortic stenosis (AS). METHODS AND RESULTS: Fifty-five patients with moderate/severe AS underwent cardiac catheterization, transthoracic echocardiography (TTE) and CMR. Overall, 171 image-planes parallel to LAP were measured via PC-CMR between 22 mm below and 24 mm above LAP. AVA via PC-CMR was calculated as flow-volume divided by peak-velocity during systole. Stroke volume (SV) and AVA were compared to volumetric SV and invasive AVA via the Gorlin-formula, respectively. Above LAP, SV by PC-CMR showed no significant dependence on image-plane-position and correlated strongly with volumetry (rho: 0.633, p < 0.001, marginal-mean-difference (MMD): 1 ml, 95 % confidence-interval (CI): -4 to 6). AVA assessed in image-planes 0-10 mm above LAP differed significantly from invasive measurement (MMD: -0.14 cm2, 95 %CI: 0.08-0.21). In contrast, AVA-values by PC-CMR measured 10-20 mm above LAP showed good agreement with invasive determination without significant MMD (0.003 cm2, 95 %CI: -0.09 to 0.09). Within these measurements, a plane 15 mm above LAP resulted in the lowest bias (MMD: 0.02 cm2, 95 %CI:-0.29 to 0.33). SV and AVA via TTE correlated moderately with volumetry (rho: 0.461, p < 0.001; bias: 15 ml, p < 0.001) and cardiac catheterization (rho: 0.486, p < 0.001, bias: -0.13 cm2, p < 0.001), respectively. CONCLUSION: PC-CMR measurements at 0-10 mm above LAP should be avoided due to significant AVA-overestimation compared to invasive determination. AVA-assessment by PC-CMR between 10 and 20 mm above LAP did not differ from invasive measurements, with the lowest intermethodical bias measured 15 mm above LAP.

Cardiac exercise imaging using a 3-tesla magnetic resonance-conditional pedal ergometer: Preliminary results in healthy volunteers and patients with known or suspected coronary artery disease.

BACKGROUND: Cardiac magnetic resonance imaging (CMR) remains underutilized as an exercise imaging modality, mostly because of the limited availability of MR-compatible exercise equipment. This study prospectively evaluates the clinical feasibility of a newly developed MR-conditional pedal ergometer for exercise CMR METHODS: Ten healthy volunteers (mean age 44 ± 16 years) and 11 patients (mean age 60 ± 9 years) with known or suspected coronary artery disease (CAD) underwent rest and post-exercise cinematic 3T CMR. Visual analysis of wall motion abnormalities (WMA) was rated by 2 experienced radiologists, and volumes and ejection fractions (EF) were determined. Image quality was assessed by a 4-point Likert scale for visibility of endocardial borders. RESULTS: Median subjective image quality of real-time cine at rest was 1 (interquartile range [IQR] 1-2) and 2 (IQR 2-2.5) for post-exercise real-time cine (p = 0.001). Exercise induced a significant increase in heart rate (62 [62-73] to 111 [104-143] bpm, p < 0.0001). Stroke volume and cardiac index increased from resting to post-exercise conditions (85 ± 21 to 101 ± 19 mL and 2.9 ± 0.7 to 6.6 ± 1.9 L/min/m2, respectively; both p < 0.0001), driven by a reduction in end-systolic volume (55 ± 20 to 42 ± 21 mL, p < 0.0001). Patients (2/11) with inducible regional WMA at high-resolution postexercise cine imaging revealed significant coronary artery stenosis in subsequently performed invasive coronary angiography. CONCLUSIONS: Exercise-CMR using our newly developed 3T MR-conditional pedal ergometer is clinically feasible. Imaging of both cardiac response and myocardial ischemia, triggered by dynamic stress, is rapidly conducted while the patient is near their peak heart rate.

Prognostic value of pulmonary transit time by cardiac magnetic resonance imaging in ST-elevation myocardial infarction.

OBJECTIVES: To investigate the prognostic value of pulmonary transit time (pTT) determined by cardiac magnetic resonance (CMR) after acute ST-segment-elevation myocardial infarction (STEMI). METHODS: Comprehensive CMR examinations were performed in 207 patients 3 days and 4 months after reperfused STEMI. Functional parameters and infarct characteristics were assessed. PTT was defined as the interval between peaks of gadolinium contrast time-intensity curves in the right and left ventricles in first-pass perfusion imaging. Cox regression models were calculated to assess the association between pTT and the occurrence of major adverse cardiac events (MACE), defined as a composite of death, re-infarction, and congestive heart failure. RESULTS: PTT was 8.6 s at baseline and 7.8 s at the 4-month CMR. In Cox regression, baseline pTT (hazard ratio [HR]: 1.58; 95% CI: 1.12 to 2.22; p = 0.009) remained significantly associated with MACE occurrence after adjustment for left ventricular ejection fraction (LVEF) and cardiac index. The association of pTT and MACE remained significant also after adjusting for infarct size and microvascular obstruction size. In Kaplan-Meier analysis, pTT ≥ 9.6 s was associated with MACE (p < 0.001). Addition of pTT to LVEF resulted in a categorical net reclassification improvement of 0.73 (95% CI: 0.27 to 1.20; p = 0.002) and integrated discrimination improvement of 0.07 (95% CI: 0.02 to 0.13; p = 0.007). CONCLUSIONS: After reperfused STEMI, CMR-derived pTT was associated with hard clinical events with prognostic information independent of and incremental to infarct size and LV systolic function. KEY POINTS: • Pulmonary transit time is the duration it takes the heart to pump blood from the right chambers across lung vessels to the left chambers. • This prospective single-centre study showed inferior outcome in patients with prolonged pulmonary transit time after myocardial infarction. • Pulmonary transit time assessed by magnetic resonance imaging added incremental information to established prognostic markers.